Outraged at relentless extortion, kidnapping and theft as a wave of drug-related violence washes over Mexico, farmers, shopkeepers and other residents in the mountainous southern state of Guerrero are taking the law into their own hands as "community police."

Both state and federal police as well as the military leave them to their own devices, manning checkpoints at entries to towns, but venturing no farther.

T-shirts pulled over their faces with holes cut for the eyes and nose, dozens of gunmen on Thursday flanked the tiny square in the hamlet of El Mezon, where more than 50 prisoners were paraded in public and accused of crimes from murder to rape to theft. No real evidence against them was presented.

The vigilante justice underscores a serious challenge facing new President Enrique Pena Nieto, who has vowed to shift the focus away from a head-to-head fight with drug-smuggling cartels that has killed up to 70,000 people in the past six years and to a more effective campaign against extortion and violence.

He plans to create a civilian-led police force made up of former military personnel that will replace the armed forces in the field, although until then, the government will keep troops out on patrol to deter violence.

Many Mexicans have little faith in police forces or the justice system. In this corner of the country, they are taking on the job themselves.

One of the gunmen watching over the alleged criminals on Thursday wore a Mexican "lucha libre" wrestler's mask, another a Spider-Man hood and a shotgun slung over his back. Some curled their fingers nervously over triggers.

They paraded the accused in groups of five in front of hundreds of onlookers. A collective gasp rose when one man was accused of murder by dismembering, a common trademark of gruesome gangland killings. He stared back at the crowd with an impassive smile.

Some local leaders gave testimony about how they themselves had been kidnapped by the accused. Sentencing will come later, organizers say.

"Many people saw it when they grabbed me. They stroked my shoulder and said they would kill me," one community police leader told the assembly.

"In my mind, I am dead, I haven't been able to get over it."

EXTORTION, KIDNAPPINGS

Communities in the folds of rugged mountains east of the once-thriving and now gang-infested beach resort of Acapulco say police are often in cahoots with criminals, do nothing when crimes are reported and ask for bribes themselves.

Extortion has flared in and around Acapulco over the past five years after two cartels clashed and one fragmented, creating a series of mini-cartels and kidnap gangs.

"We are victims of extortion, of injustice. We have been abused," said Bruno Placido Valerio, who coordinates community police groups in 20 towns and villages - a total of about 240 gunmen.

"The people are indignant at so much abuse. But we are not seeking anarchy or aiming to take justice into our own hands, but rather find a way out from the problem we are living with."

While community self-protection is a tradition in some parts of Mexico, these more radical community policing groups are an offshoot that started to form in early January.

His eyes peering out from behind a black ski-mask and clutching an aging .22-caliber rifle, a man who goes by the nickname "El Ciclon" or "The Cyclone," kept watch over residents of nearby communities attending the start of Thursday's "trial."

He and others covered their faces to remain anonymous and avoid reprisals from friends of the captives, or from government authorities.

"The people are fed up," the 45-year-old farmhand said. "Our government doesn't back us, so we decided to try to clear away all the bad people. We have to get rid of these animals."

On the eve of the trial, Guerrero state officials staged a last-ditch push to defuse the situation, but to no avail. The communities must now debate whether to impose their own punishments, or opt to turn them over to the real courts.

Some are demanding an eye for an eye.

RAPISTS 'SHOULD BE RAPED'

"They must be punished in line with the crime," said Odila Gonzalez Rios, who oversees community policing in the settlement of Copala, near the Pacific coast. "If they have raped, then they should be raped to see how it feels."

"If they have killed? The same. ... They must die, because otherwise this will never end," she said. "Do to them what they have done to others."

Acapulco last year earned the dubious distinction of being the murder capital of Mexico.

The community policing "people power" approach comes at a cost. With so many guns openly held against the law, school absenteeism has soared.

"Closing schools is no way to combat the social cancer of insecurity," said Silvia Romero Suarez, Guerrero state's education minister. "It impacts our schools because teachers are afraid and parents fear sending their children to class."

The flourishing of community police groups in Colombia was a major factor in a deep spiral of violence that country grappled with as drug gangs co-opted them in the fight against Marxist guerrillas.

Mexico's government now faces a careful balancing act in handling the issue to avoid stoking demands for self-determination elsewhere, like in the southern state of Chiapas.

In the meantime, it is allowing gunmen to operate outside the law.

"This is a violation of human rights. They are violating people's right to freedom," said Oscar Ortiz, a law professor based in Acapulco. "The Mexican state, and that of Guerrero in particular, should get into gear because you cannot permit the law to be broken like this."

But some local officials insist the push for justice is forcing criminals to think again and making the area safer.

"They have filled us, the authorities, with courage, I can't hide or deny that," said Severo Castro Godinez, mayor in the town of Ayutla.

"Fortunately today, thanks to this movement, Ayutla is at peace. ... The community police are good people. They are responsible citizens. They are not looking to kill, they are looking to correct social behavior." (Additional reporting by Luis Enrique Martinez; Editing by Kieran Murray)